Conventional color diffusion transfer photographic film units are generally classified into a peel-apart type and a non-peel-apart type.
In the separation type ("peel-apart type") film unit, photosensitive layers and a dye-receiving layer are each formed on a different support and dye images transferred onto the dye image-receiving layer are obtained by superposing the photosensitive element on the dye image-receiving element after imagewise exposure, spreading a processing composition between the elements, and thereafter, separating the image-receiving element from the photosensitive element.
Since the dye images formed in the imagereceiving layer coated on a support can be directly viewed, the reduction of image quality found in non-peel-apart units described below does not occur, and very excellent color reproduction is obtained However, it is inconvenient to superpose the photosensitive element and the image-receiving element in the camera, and in handling the processed film the alkaline processing liquid after separation is sticky and is liable to stick to surrounding materials.
In the non-peel-apart type film unit, a dye image-receiving layer and silver halide emulsion layers are formed between a transparent support and another support, and the dye image-receiving layer and the silver halide emulsion layers can be formed on the same transparent support or each formed on a different support.
In the former case, a white reflective layer is formed between the image-receiving layer and the silver halide emulsion layer and in the latter case, a white pigment is incorporated in a processing composition which is spread between the image-receiving layer and the silver halide photographic emulsion layers for viewing the dye images transferred onto the image-receiving layer.
These non-peel-apart type film units can be very easily handled without the inconvenience in handling caused by stickiness of the processing liquid after separation and superposing the film sheets in the camera. However, the color images formed are viewed through a transparent support in this type, which unavoidably reduces the image quality of color images, by the reduction in color saturation caused by surface reflection, the insufficiency of whiteness in background areas caused by the deficiency in reflectance of the white reflection layer, etc. Furthermore, silver-halide emulsion layers, a pod for processing liquid, a cover sheet, etc., remain in the color print after processing without being separated, so that the thickness of the color print is inconveniently thicker.
Separation type color diffusion transfer photographic materials are used in various fields such as, for example, ID cards, certificates, etc., because of their simplicity, quickness, and high image quality. In these cases, it is required to coat the back surface of each color print with adhesives after processing and stick it to a proper member, such as sheet, etc., and a convenient method for simplifying such a troublesome post treatment is desired.
Techniques for removing processed silver halide emulsion layer(s), a cover sheet, etc., using a separating layer were disclosed but such conventional techniques could not provide excellent handling qualities and color images having excellent quality.
These conventional techniques are described, for example, in U.S. Pat. Nos. 3,730,718, 4,499,174 and 4,459,349, which disclose a technique of forming, in sequence, an image-receiving layer, a separating layer, and photosensitive layer(s) on a support and, after processing, separating unnecessary portions such as photosensitive layer(s), processing liquid, cover sheet, etc., for reducing the thickness of the color print obtained after processing, i.e., for reducing undesired thickness in a non-peel-apart unitary type film unit. However, these techniques relate to film units for viewing color images formed in the image-receiving layer through the transparent support and, hence, in these techniques the color prints have insufficient image quality caused by the reduction of color saturation caused by the surface reflection of the transparent support, and also by insufficient whiteness of he white reflection layer.
Also, U.S. Pat. Nos. 4,328,301, 3,658,524, British Pat. No. 641,355, and Research Disclosure, No. 16462 (Dec., 1977) disclose techniques of forming, in sequence, a dye image-forming layer, a separating layer, and photosensitive layer(s) on a support (including a paper support) and, after processing, separating the photosensitive layer(s) to provide a color print. However, they do fail to disclose a unitary type film unit capable of being processed from development to stabilization in the film unit. For example, U.S. Pat. No. 4,328,301 discloses a technique of processing the photographic material by immersing it in a processing bath and then separating the photosensitive layer(s) in a wet state. Also, Research Disclosure, No. 16462 (Dec., 1977) discloses a technique of developing the photographic material by uniformly spreading a viscous processing liquid on the photosensitive element and then separating the photosensitive layer(s) in water. In other words, the photographic materials disclosed each requires a processing bath for the processing. This is also clear from the fact that the photographic materials do not include a layer having a development stopping function or a neutralizing function. These photographic materials having no neutralizing function cannot provide stable color images without stabilization in a processing bath, and if such processing is performed, the techniques are not instant or convenient.
Furthermore, the material disclosed in Research Disclosure, No. 16462 (Dec., 1977) is processed in the dark, and cannot be processed in a bright room.
Also, U.S. Pat. Nos. 3,445,228, 3,227,550, 3,227,552 and British Pat. No. 641,355 disclose the use of a separating layer in a color diffusion transfer photographic material using a color developing agent and U.S. Pat. No. 3,445,228 discussed above discloses an acid neutralizing layer formed between a dye image-receiving layer and a support. However, these techniques use dye image-forming methods that give prints insufficient in quality.
These color image-forming methods use a color developer for forming dyes, but the color developing agent remains in the dye image-receiving layer to form significant color stains, and a print having clear background cannot be obtained. Furthermore, the abovedescribed U.S. Pat. No. 3,227,550 does not disclose processing under bright room light.
U.S. Pat. No. 4,401,746 discloses a unitary type film unit having, in sequence, a dye image-receiving layer, a separating layer, and photosensitive layer(s) on a support (including a paper support); removing, after processing, unnecessary photosensitive layer(s), processing composition, etc.; and suggests an acid neutralizing layer formed between the support and the dye image-receiving layer. However, the film unit disclosed in the patent must be processed in the dark, and is not an "instant" material that can be easily processed in a bright room.
Also, U.S. Pat. Nos. 3,820,999, 3,220,835, 2,759,825, 2,614,926, 2,543,181 and 3,409,430 disclose techniques of separating unnecessary photosensitive layers using a separating layer after processing, but these techniques relate to black-and-white photographic materials using a silver salt diffusion transfer process.
Furthermore, U.S. Pat. Nos. 4,359,518, 3,674,482 and 4,383,022 disclose the use of a separating layer for additive color process color photographic materials utilizing silver salt diffusion transfer, but the color photographic materials disclosed do not contain a layer having a neutralizing function. Moreover, they cannot be processed in bright room light.